This component of the program project will examine the development of sensory behavior and learning in the fetus. The Principal Investigators have conducted research for a number of years in this area with fetal rodents, and the analytic techniques, experimental design considerations, and general findings of their previous research will be applied to study behavioral organization, responsiveness to controlled chemosensory stimulation, habituation and learning in the sheep fetus. Several different parameters of fetal responsiveness will be measured, including electrocortical activity (ECoG) and other measures of fetal physiology (e.g., eye movements, breathing, heart rate). Additionally, selected fetal muscles will be instrumented to measure EMG patterns in the oral-facial area, head, and limbs. A series of experiments will be conducted to test the following hypotheses: (1) the sheep fetus will exhibit behavioral responsiveness to various forms of sensory stimulation during the last third of gestation; (2) fetal behavior will be modified following experience with a particular stimulus, including a decrement in quantitative measures of responsiveness following repeated presentation of a stimulus; (3) experiential changes in fetal responsiveness will be attributable to habituation and not to peripheral effects, such as receptor adaptation or effector fatigue; and (4) the fetus will exhibit the capacity to form associations between different chemosensory stimuli in utero and retain learned information from early chemosensory experiences to affect behavior at subsequent points in gestation.